## Table 1 |
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Extracted factors and outcome measures |
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Factor/Outcome measure |
Data type |
Final categories* or unit |
Reference category for regression analyses |

Rat property factors |
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Strain |
Category | I. Sprague Dawley |
Sprague Dawley |

II. Wistar |
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III. SHR |
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IV. WKY |
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V. Other strains |
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Sex |
Category | I. Male |
Male |

II. Female |
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III. Ovx female |
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IV. Mix or not specified |
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Elderly rats ** |
Category, Binomial | [No] | [No] |

[Yes] | |||

Weight |
Continuous | Grams | NA |

Animal exclusion rate |
Continuous | % | NA |

Anesthesia factors |
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Type of anesthetic |
Category | I. Inhalation anesthetic |
Inhalation anesthetic |

II. Chloral hydrate |
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III. Ketamine |
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IV. Barbiturates and benzodiazepines |
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V. Other anesthetics |
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Intubation |
Category, Binomial | [No] | [No] |

[Yes] | |||

Awakening of rats during occlusion |
Category, Binomial | [No] | [No] |

[Yes] | |||

Temperature feedback system |
Category, Binomial | [No] | [No] |

[Yes] | |||

Electroencephalographic surveillance |
Category, Binomial | [No] | [No] |

[Yes] | |||

Blood pressure monitored |
Category, Binomial | [No] | [No] |

[Yes] | |||

Heart rate monitored |
Category, Binomial | [No] | [No] |

[Yes] | |||

Blood gases/O_{2}saturation analyzed |
Category, Binomial | [No] | [No] |

[Yes] | |||

Blood hemoglobin concentration analyzed |
Category, Binomial | [No] | [No] |

[Yes] | |||

Blood glucose concentration analyzed |
Category, Binomial | [No] | [No] |

[Yes] | |||

Postoperative antibiotics |
Category, Binomial | [No] | [No] |

[Yes] | |||

Focal ischemia procedure factors |
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Type of middle cerebral artery occlusion procedure |
Category | I. Intraluminal filament |
Intraluminal filament |

II. Direct, mechanical*** |
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III. Embolic |
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IV. Photothrombotic |
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V. Endothelin injection |
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Occlusion duration**** |
Category | I. Short transient (up to 60 minutes) |
Short transient (up to 60 minutes) |

II. Long transient (>60 min) |
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III. Permanent |
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Occluding filament type (Only studies using the intraluminal filament method) |
Category | I. Uncoated |
Uncoated |

II. Silicon coated |
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III. Poly-L-Lysine coated |
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IV. Other coatings |
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Analysis procedure factors |
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Time after focal ischemia for evaluation of damage |
Continuous | Hours | NA |

Type of infarct size evaluation |
Category | I. TTC |
TTC |

II. Radiology |
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III. Acidic/Basic stain or silver stain histology |
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IV. Immunohistology |
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Edema correction used |
Category, Binomial | [No] | [No] |

[Yes] | |||

Blinding of infarct size determination procedure |
Category, Binomial | [No] | [No] |

[Yes] | |||

Criteria for excluding rats |
Category | I. None |
None |

II. Observed absence of cerebral blood flow reduction |
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III. Lack of functional deficit |
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IV. Too small infarct |
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V. Other pathology in animal |
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Outcome measures |
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Infarct size coefficient of variation |
Continuous | % | NA |

Mortality rate |
Continuous | % | NA |

* Only categories represented by at least 5 control groups were included in the analysis
to avoid statistically inadequate attribution of explanatory value to too small categories.
Categories represented by less than 5 control groups were in the analysis included
in an *Others* category. Further, some other reductions in number of categories were performed,
as presented below.

** Elderly rats were defined as being >12 months of age at time of ischemic insult.

*** *Direct, mechanical* refers to all MCAo procedures where the MCA is mechanically occluded from the outside,
for example by clips, cauterization or ligation.

**** Only methods including actions taken to ensure reperfusion (such as removing the occluding intraluminal filament or arterial clip) were considered transient.

Ström * et al.*

Ström * et al.* *BMC Neuroscience* 2013 **14**:41 doi:10.1186/1471-2202-14-41